WoodSolutions Teaching Resource. AS Annotated Standard. Section 2 Terms & Definitions 2010

Transcription

1 WoodSolutions Teaching Resource AS Annotated Standard Section Terms & Definitions 010 JUNE 010

2 Copright 010 WoodSolutions Australia SAI Global has given copright permission to Forest & Wood Products Australia, trading as WoodSolutions Australia to publish and distribute an annotated version of the standard to teachers for educational purposes. This is not for general distribution. The annotated standard for teachers is published in 15 sections including appendices and is available for download from education.woodsolutions.com.au. Disclaimer WoodSolutions is resourced b Forest and Wood Products Australia Limited (FWPA). Whilst all care has been taken to ensure the accurac of the information contained in this publication, Forest and Wood Products Australia Limited (FWPA) and other contributors disclaim, to the full etent permitted b law, all and an liabilit for an damage or loss, whether direct or indirect, special or consequential, arising directl or indirectl out of use of or reliance on this guide, whether as a result of negligence or otherwise. Visit For more than three thousand pages of information, inspiration and technical publications on everthing about timber in the built environment WoodSolutions is an initiative of Forest & Wood Products Australia, which is jointl funded b the Australian forest and wood products industr and the Commonwealth Government. JUNE 010

3 Teaching Guide AS 1684.&3-1 SECTION : TERMINOLOGY AND DEFINITIONS.1 GENERAL The terminolog and definitions given in this Section shall be used in conjunction with the requirements of this Standard. The terminolog used b the building industr varies greatl between states, regions within states and even between those working in the same region. Where possible, the more commonl used terms have been adopted b this standard.. TERMINOLOGY OF FRAMING MEMERS Figure.1 details floor, wall and ceiling framing members in general. An alternative wall frame detail is given in Figure 6.1(b). Figures. to.7 appl to roof framing. Hanging beam Cleat (hanger) Rafter Fascia Soffit bearer Lintel Ledger Jack stud Sill trimmer Jamb stud Jack stud Ceiling joist Jack ceiling joist (trimmer) Top wall plate race Nogging Common stud ottom wall plate Floor joist earer Termite shield (ant cap) Stump (post, pier) NOTE: The ceiling and floor joists are shown parallel to the eternal loadbearing wall for clarit. The more usual case in practice is for the joists to be located perpendicular to the eternal wall. Lintel location ma also var (see Figure 6.8). FIGURE.1 FRAMING MEMERS FLOOR, WALL AND CEILING JUNE 010

4 Teaching Guide AS 1684.&3 - Ridgeboard Fascia Collar tie Underpurlin Common rafter Top plate Raking plate Solid blocking Ceiling joist argeboard (verge, verge rafter) Outrigger NOTE: Some members have been omitted for clarit. FIGURE. FRAMING MEMERS GALE ROOF CONSTRUCTION Ridgeboard Hip rafter Creeper rafter roken hip Cripple creeper rafter Jack rafter (crown end) Valle rafter Valle creeper rafter Collar tie Hip rafter Hanging beam Roof strut Underpurlin Top plate Rafter Ceiling joist NOTE: Some members have been omitted for clarit. Jack rafter (crown end) Jack ceiling joist Creeper rafter Fascia min. FIGURE.3 FRAMING MEMERS HIP AND VALLEY ROOF CONSTRUCTION JUNE 010

5 Teaching Guide AS 1684.&3-3 Rafter Valle creeper rafter Scotch valle (pitching plate) Top plate Ridgeboard Ceiling joist Fascia Rafter NOTE: Some members have been omitted for clarit. FIGURE.4 FRAMING MEMERS SCOTCH VALLEY CONSTRUCTION Intermediate beam Ridge beam Raking top plate Verge rafter Rafter supporting roof and ceiling loads ( roof beam) Eaves beam Studs supporting concentrations of loads NOTE: Some members have been omitted for clarit. FIGURE.5 FRAMING MEMERS CATHEDRAL ROOF CONSTRUCTION JUNE 010

6 Teaching Guide AS 1684.&3-4 Outrigger Solid blocking Fascia argeboard Top plate argeboard (verge, verge rafter) Raking plate FIGURE.6 SKILLION ROOF Standard truss Structural fascia Gable end stud Outriggers End wall arge ( verge rafter) Verge overhang Raking truss ( gable truss) NOTE: This diagram applies to verge overhangs greater than 300 mm from the raking or gable truss (see AS 4440). FIGURE.7 GALE END TRUSSED ROOF.3 VERTICAL LAMINATION.3.1 Vertical nail lamination Vertical nail lamination shall be permitted to achieve the required breadth for the larger section sizes given in the Span Tables of the Supplements using thinner and more readil obtainable sections. This is onl permissible using seasoned timber laminations of the same timber tpe (e.g. hardwood + hardwood, softwood + softwood) and stress grade. Laminations shall be unjoined in their length. Nails shall be a minimum of.8 mm in diameter and shall be staggered as shown in Figure.8(a), and shall be through-nailed and clinched, or nailed from both sides. JUNE 010

7 Teaching Guide AS 1684.&3-5 Where screws are used in lieu of nails, the shall be minimum No. 10 screws at the same spacing and pattern, provided that the penetrate a minimum of 75% into the thickness of the final receiving member..3. Lamination of spaced ring beams Ring beams that are made up of two spaced members shall be laminated in accordance with Figure.8(b) (a) Vertical nail lamination (strutting beam shown) (b) Lamination of spaced ring beams FIGURE.8 VERTICAL LAMINATION JUNE 010

8 Teaching Guide AS 1684.&3-6 Direction of load FIGURE.8 VERTICAL NAIL LAMINATION (EXAMPLE STRUTTING EAMS) Direction of load The term 'vertical nail lamination' is used because the loads applied to a house frame are predominantl vertical. The load applied to nail laminated timber must alwas be in the direction O of the depth of the timber and at 90 to the nails. If the load on a nail laminated member is in the opposite direction to the depth and in line with the nails, the nails will be insufficient to prevent movement between the two pieces. Due to this movement or 'slippage' between the pieces the will act individuall rather than as a single member.. Direction of load Load Load Movement occurs between the pieces Direction Of load The nail size and spacing that applies to 'vertical nail lamination' is also applicable to members used horizontall where the direction of the applied load is horizontal. There are few situations in a house frame where the main direction of load on a member is horizontal. Generall horizontal loads are the result of wind or earthquake loads. Sill trimmers are perhaps the onl structural member where the onl real load is due to wind. Horizontal wind loads in high wind areas on studs ma govern studs sizes. Studs are nail laminated as per Clause.4 and window sill/lintel trimmers are nail laminated as per wall plates Clause.5. NOTE: Top plate are an eception to the rule and can be horizontall nail laminated i.e. with the load in line with the nails. Refer Clause.5. The multiple member sizes given in the Span tables take into consideration the reduced effectiveness of this tpe of nail laminated..4 STUD LAMINATION The required size ma be built up b using two or more laminations of the same timber tpe, (e.g. hardwood + hardwood, softwood + softwood) stress grade and moisture content condition, (an unseasoned stud can NOT be laminated to a seasoned stud) provided the achieved width is at least that of the nominated size. Studs up to 38 mm thick shall be nailed together with one 75 mm nail at maimum 600 mm centres. Studs over 38 mm but not eceeding 50 mm thick shall be nailed with one 90 mm nail at maimum 600 mm centres (see Figure.9). JUNE 010

9 Teaching Guide AS 1684.&3-7 Where screws are used in lieu of nails, the shall be minimum No. 10 screws at the same spacing and pattern, provided that the penetrate a minimum of 75% into the thickness of the final receiving member. Posts shall not be nail-laminated. Posts are not to be nail laminated because the do not have the lateral restraint in the opposite direction to the lamination that studs receive from nogging. No lateral restraint Lateral restraint from nogging POST STUD Plates nailed together over each stud Joints min. 100 mm apart and staggered Where joints occur in either top plate between studs, and where rafter or truss bears onto top plates, additional blocking shall be provided 600 ma. Multiple studs nailed together at 600 mm ma. centres NOTE: Refer to Section 9 for other nominal fiing requirements including plates to studs. FIGURE.9 STUD/PLATE LAMINATION.5 HORIZONTAL NAIL LAMINATION WALL PLATES ONLY Wall plates that are made up of more than one section (e.g. /35 70) shall be horizontall nail-laminated in accordance with Figure.9 and using (a) two 75 mm long nails for plates up to 38 mm deep, or (b) two 90 mm long nails for plates up to 50 mm deep (see also Clause 9..10). A minimum of two nails shall be installed at not greater than 600 mm centres along the plate. Where more than two plates are used, the nailing requirement applies to each lamination JUNE 010

10 Teaching Guide AS 1684.&3-8 All joins in multiple bottom plates shall occur over solid supports such as floor joists, solid blocking between bottom plate and bearer or concrete slab. Joins in adjacent plates are to be a minimum of 100 mm apart. Joins in either plate ma be made between studs. (see Clause & Figure 9. (c) If a loadbearing member falls between studs where either plate is joined, the plates must be reinforced with an additional piece of timber of the same size as the individual plate being reinforced. (also refer Clause 6...3) To avoid splitting, nails can be offset to the sides of studs b 50 mm. 50 mm / mm nails / mm nails at each stud. either side off joins. 100 mm min between joins Ribbon plate construction locking piece required if a rafter, truss, floor joist or other point load falls between the studs where a join occurs. locking will also be required if an uplift loads fall between tie-down points where a join occurs..6 LOAD WIDTH AND AREA SUPPORTED.6.1 General The load width and area supported are used to define the amount of dead, live and wind load that is imparted onto a member. Load width, coupled with another geometric descriptor such as spacing or span will define an area of load that a member is required to support. To determine a timber size for a particular member, the amount of dead & live load that is to be applied to that member must be determined prior to entering the span tables. The amount of load is directl proportional to the AREA of roof and/or floor that this member supports. For most members, this AREA is not actuall calculated but Load width,.. plus.. another geometric descriptor such as spacing (or span) will define an area of load that a member is required to support. Note: Uplift loads in high wind areas ma dictate the size of a member. The magnitude of the uplift load will (generall) be in proportion to the area that is supported. Floor load width (FLW), ceiling load width (CLW) and roof load width () shall be determined from Clauses.6. to.6.4. JUNE 010

11 (b) Supported balcon (a) Cantilevered balcon Teaching Guide AS 1684.&3-9 For uplift due to wind loads, the definition uplift load width (ULW) is used as ULWs ma differ significantl from s depending upon where the structure is tied down. Refer to Section 9 for definition of ULW. For most houses, the uplift load width and roof load width is measured between the same points. The actual measurements will var however because is measured on the rake of the roof between the two points and ULW is measured horizontall between the same points. There are occasionall situations where the points of measurement of ULW ma differ significantl from the points for. Such cases are discussed in Section Floor load width (FLW) Floor load width (FLW) is the contributor width of floor, measured horizontall, that imparts floor load to a supporting member. FLW shall be used as an input to Span Tables in the Supplements for all bearers and lower store wall framing members. The FLW input is illustrated in Figures.10 and.11. Of the total load on a floor joist, half will go to the bearer on one end and half to the bearer on the other end. So floor load width (FLW) is simpl half the floor joist span on either side of the bearer, added together. The onl eception is where there is a cantilever. In this situation, the total cantilever distance plus half of the floor joist span is used. Tpe of construction Location Floor load width (FLW) earer A FLW = a FLW FLW FLW earer FLW = a A C earer C FLW = earer A FLW = FLW FLW FLW FLW earer FLW = A C D z z earer C FLW = earer D FLW = z FIGURE.10 FLOOR LOAD WIDTH (FLW) SINGLE OR UPPER-STOREY CONSTRUCTION JUNE 010

12 Teaching Guide AS 1684.&3-10 FLW FLW FLW A C D FLW FLW FLW FLW a z Tpe of construction Location Floor load width (FLW) (a) Lower store loadbearing walls Wall A Upper FLW = a Wall Upper FLW = Wall C Upper FLW = Wall D N/A* earer A Upper FLW = a Lower FLW = (b) earers supporting lower store loadbearing walls earer earer C earer D Upper FLW = Lower FLW = Upper FLW = z Lower FLW = Upper FLW = N/A* Lower FLW = z * See single or upper-store construction. FIGURE.11 FLOOR LOAD WIDTH (FLW) TWO-STOREY CONSTRUCTION Eamples of calculating and appling FLW to the span tables are given in Section 4 Floor Framing. JUNE 010

13 Teaching Guide AS 1684.& Ceiling load width (CLW) Ceiling load width (CLW) is the contributor width of ceiling, usuall measured horizontall, that imparts ceiling load to a supporting member. CLW shall be used as an input to Span Tables for hanging beams, counter beams and strutting/hanging beams. The CLW input is illustrated in Figure.1. Ceiling load width (CLW) is simpl the sum of half the ceiling joist spans on each side of the Hanging beam or Strutting/ hanging beam. D CLW CLW A C E Location Walls A, & C eam D (Hanging beam) eam E (Strutting/hanging beam) Ceiling load width (CLW) N/A* CLW = CLW = * CLW is not required as an input to the Tables for wall framing or bearers supporting loadbearing walls. FIGURE.1 CEILING LOAD WIDTH (CLW) * CLW is not required as an input to the Tables for wall framing or bearers supporting loadbearing walls because these loads are alread included in the Sheet or Tile roof loads required as input to the tables for these members..6.4 Roof load width () The roof load width () is used as a convenient indicator of the roof loads that are carried b some roof members and loadbearing wall members and their supporting substructure. The value shall be used as an input to the relevant wall framing and substructure Span Tables. Figures.13 to.16 define in relation to various tpes of roof construction. Of the roof load on members such as rafters and trusses, half will go to the supporting wall or beam on one end and half to the supporting wall or beam on the other end. So roof load width () is simpl half the particular member s span, plus an overhang, measured on the rake of the roof. JUNE 010

14 (c) Skillion (b) Cathedral (a) Truss Teaching Guide AS 1684.&3-1 NOTE: Amendment 1, deleted reference to s in the diagrams in Figures.13 and.14 but the have been retained below for clarit. Tpe of construction Wall Roof load width () for member sizing A = a a b A The roof loads on trusses are distributed equall between walls 'A' and ''. = b A = a a b A The roof loads on trusses with unequal pitches are also distributed equall between walls 'A' and ''. = b a + b A = a = b A C The roof loads on rafters in a cathedral or skillion roof are distributed equall between the wall or beam on either end of the rafter. C = a b A = a = b A FIGURE.13 ROOF LOAD WIDTH () NON-COUPLED ROOFS JUNE 010

15 Teaching Guide AS 1684.&3-13 Tpe of construction Wall Roof load width () for member sizing a b A = + a = + b A (a) No ridge struts + A = a a b = b A C (b) Ridge struts Although it states that a is not applicable (N/A) for wall C, a measurement equal to the shown above and calculated on the right, will be required to calculated the area supported b the studs supporting concentrated loads in wall C C N/A* = + * ma not be applicable where strut loads are supported b studs supporting concentrations of load and the remainder of wall C is deemed non-loadbearing. In this case, the roof area supported shall be determined for the studs supporting concentrated loads. FIGURE.14 ROOF LOAD WIDTH () COUPLED ROOFS WITH NO UNDERPURLINS JUNE 010

16 Teaching Guide AS 1684.&3-14 Tpe of construction For a pitched roof without ridge struts, it is assumed that some of the load from the un-supported ridge will travel down the rafter to walls 'A' and ''. The 's for these walls are increased accordingl. Wall A Roof load width () for member sizing = a a 1 3 b = b 3 (a) No ridge struts A Although 's are not shown for the underpurlins these 's are required b the underpurlin span table and also to calculate the area supported b the studs supporting concentrated loads at the end of struts and/or strutting beams that support the underpurlins. 1 3 RWL = = = 3 3 a b A = a 4 = b 6 (b) Ridge struts A C Although it states that a is not applicable (N/A) for wall 'C' or the underpurlins, these 's will be required to calculate the area supported b the 'studs supporting concentrated loads' in wall 'C' and at the end of struts and/or strutting beams that support the underpurlins. C = = = * ma not be applicable where strut loads are supported b studs supporting concentrations of load and the remainder of wall C is deemed non-loadbearing. In this case the roof area supported shall be determined for the studs supporting concentrated loads. NOTES: Collar ties have been omitted for clarit. FIGURE.15 ROOF LOAD WIDTH () COUPLED ROOFS WITH UNDERPURLINS 1 3 N/A* = JUNE 010

17 Teaching Guide AS 1684.&3-15 Tpe of construction Wall Roof load width () for member sizing a b A = a 4 = b 6 A C a) Cathedral Framed s for underpurlins are as per Figure.15 (b) C = a b A = a = b A C Cathedral Truss C = a V + v A = a A (c) Verandah = for main roof + v NOTE: Collar ties have been omitted for clarit. FIGURE.16 ROOF LOAD WIDTH () COMINATIONS AND ADDITIONS JUNE 010

18 Teaching Guide AS 1684.& Area supported The area supported b a member is the contributor area, measured in either the roof or floor plane, that imparts load onto supporting members. The roof area shall be used as an input to Span Tables in the Supplements for strutting beams, combined strutting/hanging beams, combined strutting/counter beams and studs supporting concentrated loads and posts. The floor area shall be used as an input to Span Tables in the Supplements for studs supporting concentrated loads and posts. Tpical area supported inputs for roofs and floors is illustrated in Figure.17. A Strut Strut Underpurlin Rafter Span A Strut Strut Underpurlin Rafter Span Strut Strut Strutting eam Span Strutting eam Roof area supported = (1/)A (1/) (ridge strutted) Strutting eam Span Strutting eam Roof area supported = (1/)A (3/4) (ridge not strutted) (a) Tpical roof area supported b strutting beam FIGURE.17 AREA SUPPORTED In the eample above, some of the roof load carried b the rafters is supported b an underpurlin that is supported b struts and a strutting beam. The Strutting eam span table (Table 7) requires a Roof Area Supported (m ) input. The strutting beam onl supports a single strut so the roof area required to be calculated is the roof area supported b this strut. This is calculated as follows:- Strutted Ridge - The sum of, half the underpurlin spans either side of the strut (half A) (which is the of the underpurlin as shown in Figures.15), multiplied b the sum of half the rafter spans either side of the underpurlin (half ). Ridge Not Strutted - The sum of, half the underpurlin spans either side of the strut (half A) (which is the of the underpurlin as shown in Figure.15), multiplied b the sum of half the rafter span from the underpurlin to the top plate and the full span of the rafter from the underpurlin to the ridge (three quarters ). JUNE 010

19 Teaching Guide AS 1684.&3-17 C Rafter span A Joist span C 1/ rafter span A 1/ joist span 1/ eam span eam Span (Post spacing) Roof Area Supported = A 1/ earer span D earer Span D (Post Spacing) Post Floor Area Supported = C D NOTE: If the post was the central support for a continuous span verandah beam and bearer, the areas supported would be as follows: (a) Roof area supported = A/ (b) Floor area supported = C/ D (b) Tpical roof and floor area or supported b post FIGURE.17 AREA SUPPORTED JUNE 010

20 Teaching Guide AS 1684.& DEFINITIONS GENERAL.7.1 Loadbearing wall A wall that supports roof or floor loads, or both roof and floor loads..7. Non-loadbearing walls A non-loadbearing internal wall supports neither roof nor floor loads but ma support ceiling loads and act as a bracing wall. The main consideration for a non-loadbearing internal wall is its stiffness. i.e. resistance to movement from someone leaning on the wall, doors slamming shut etc. Internal wall frames that do not carr roof loads are considered non-loadbearing. The ma still be considered non-loadbearing even though the ma incorporate studs that carr ceiling loads and/or studs that support concentrated loads from hanging beams, strutting beams etc. and/or structural bracing. The studs that support concentrated loads in these walls are required to be designed accordingl. See Clause Note:The non-loadbearing internal wall frame table (Table 6.) is based on notched studs with an F4 stress grade. For internal non-loadbearing studs over 700 mm high, (or sa a instead of /90 35) studs ma be suitable if the studs were not notched and/or a higher stress grade was used. To determine alternate stud sizes to Table 6., use the Internal Load-bearing stud tables (Tables 1 & 13). Enter the table for a sheet roof with a 450 rafter/truss spacing. Providing there is a (an RWL > 0 is OK) corresponding to the required stud height and section size it can be used in this nonloadbearing application. EXAMPLE: JUNE 010

21 Teaching Guide AS 1684.&3-19 A non-loadbearing eternal wall supports neither roof nor floor loads but ma support ceiling loads and act as a bracing wall. A non-loadbearing eternal wall ma support lateral wind loads (e.g. gable or skillion end wall). Non-loadbearing eternal walls will be required to resist lateral wind loads and therefore must be designed accordingl. This is achieved b choosing a stud size from the eternal wall stud table (Tables 7 or 8) using the appropriate stud height and stud spacing, and the smallest possible roof load i.e. Sheet roof and the smallest Roof Load Width..7.3 Regulator authorit The authorit that is authorized b legal statute as having justification to approve the design and construction of a building, or an part of the building design and construction process. NOTE: In the contet of this Standard, the regulator authorit ma include local council building surveors, private building surveors or other persons nominated b the appropriate State or Territor building legislation as having the legal responsibilit for approving the use of structural timber products..7.4 Roofs Coupled roof Pitched roof construction with a roof slope not less than 10º, with ceiling joists and collar ties fied to opposing common rafter pairs and a ridgeboard at the ape of the roof (see Figure 7.1). A coupled roof sstem ma include some area where it is not possible to fi ceiling joists or collar ties to all rafters; for eample, hip ends or parts of a T- or L-shaped house. A coupled roof relies on the triangulation formed b the rafters and ceiling joist to support the roof load. The rafters and ceiling joist MUST be securel fied (coupled) together at the pitching points to form this triangulation. If this triangulation cannot be formed or the roof pitch is less than 10º, the roof must be designed as a non-coupled roof i.e. using ridge beams etc.. A coupled roof ma incorporate underpurlins, struts, strutting beams etc. The method of roof construction where the ceiling joists are fied to the rafters part wa up the rafters is NOT covered b AS 1684 and must be individuall designed b an engineer. JUNE 010

22 Teaching Guide AS 1684.&3-0 Ridge board Rafter Ceiling joist Rafters & Ceiling Joist must be fied together at the pitching points Ridge board otherwise there is nothing to stop the walls from spreading and the roof from collapsing Rafter Ceiling joist (Collar Tie) This method of roof construction is not covered b AS Non-coupled roof A pitched roof that is not a coupled roof and includes cathedral roofs and roofs constructed using ridge and intermediate beams. A non-coupled roof relies on ridge and intermediate beams to support the centre of the roof. These ridge and intermediate beams are supported b walls and/or posts at either end. Ridge eam Rafter Intermediate eam Pitched roof A roof where members are cut to suit, and which is erected on-site Trussed roof An engineered roof frame sstem designed to carr the roof or roof and ceiling, usuall without the support of internal walls. AS 1684 does not contain design or installation information for trussed roofs because the are individuall engineer designed b truss manufacturers. AS Installation of nail-plated timber trusses, provides the basic performance requirements and specifications for the bracing, connection and installation of nailplated timber trusses. JUNE 010

23 Teaching Guide AS 1684.& Span and spacing General Figure.18 illustrates the terms for spacing, span, and single and continuous span Spacing The centre-to-centre distance between structural members, unless otherwise indicated Span The face-to-face distance between points capable of giving full support to structural members or assemblies. In particular, rafter spans are measured as the distance between points of support along the length of the rafter and not as the horizontal projection of this distance Single span The span of a member supported at or near both ends with no immediate supports. This includes the case where members are partiall cut through over intermediate supports to remove spring (see Figures.18(c) and.18(d)) Continuous span The term applied to members supported at or near both ends and at one or more intermediate points such that no span is greater than twice another (see Figure.18(e)). 1/3 (000mm) 6000mm 1/3 (000mm) 1/3 (000mm) The centre support must be wholl within the middle third. Span 1 (000mm) Span (3930mm) 75mm 75mm 75mm Span is not to be greater than twice Span 1. This span is used to determine the size using the continuous span tables. JUNE 010

24 Teaching Guide AS 1684.&3 - Joists spacing (centre-line to centre-line) Joists span (between internal faces of support members) earer spacing (centre-line to centre-line) (a) earers and joists Overhang Rafter span (b) Rafter Single span (c) Two supports Saw Sawcut Joint or or lap lap Singlespan Singlespan (d) Joint or sawcut over supports Continuous span Continuous span (e) Continuous span NOTE: The design span is the average span unless one span is more than 10% longer than another, in which case the design span is the longest span. FIGURE.18 SPACING AND SPAN JUNE 010

25 Stud height Teaching Guide AS 1684.& Stress grade The classification of timber to indicate, for the purposes of design, a set of structural design properties in accordance with AS Stud height The distance from top of bottom plate to underside of top plate or the distance between points of lateral restraint provided to both the breadth and depth of the stud. Where full height studs are NOT restrained laterall b a floor or ceiling the stud height is measured between plates. Even though A this stud is full height, the stud size will be c a l c u l a t e d u s i n g t h e greater of A or Where full height studs are restrained laterall b a floor or ceiling the stud height is measured between the lateral restraint and the plate. Floor or ceiling framing providing lateral restraint in both directions. NOTE: Nogging has been omitted for clarit..7.8 Two-store In an section through the house, construction that includes not more than two levels of timber-framed trafficable floor. Trafficable floors in attics and lofts are included in the number of stores. In the subfloor of a two-store construction, the maimum distance from the ground to the underside of the lower floor bearer shall be 1800 mm. NOTE: This requirement does not preclude the application of this Standard to up to a twostore timber-framed construction supported (a) b a bearer and joist substructure designed in accordance with this Standard; or (b) b lower levels of timber wall framing or other support sstems designed in accordance with engineering principles and approved b the regulator authorit. JUNE 010

26 >1800 mm Teaching Guide AS 1684.&3-4 Although all of the buildings below compl with not more than two levels of timber framed trafficable floor, if the sub-floor or ground floor was more than 1800 mm off the ground, engineering advice should be sought for the whole structure. Also see Section 8 - Figure 8. (c) Note 1. Engineering Advice 1800 mm ma mm ma. Require d.7.9 Rim board A member, at right angles to and fied to the end of deep joists (including I-joists), that provides restraint to the joists. (see Clause ) Rim board JUNE 010